Brant,
so what a bout the people that have the tapered bearings and still get wobble? Or the guys who have more than 100 K on OEM bearings and never had the wobble? Or the guy who only had wobble once in over 300K and it was his tire?
Nobody is trying to say that anything applies 100% of the time, there are a few variables involved in this issue.
1. production tolerances in the steering components
2. assembly tolerances using those components
3. bearing adjustment variations at the factory
4. bearing adjustment variations by the owner
So based on the variations above, many combinations do exist.
Most people who encounter headshake and switch to tapered bearings report that they do not experience it again, or its effect is greatly diminished to the point where its a non-issue.
The torque spec for the tapered bearings is obviously not the same as in the manual because they're a totally different bearing type. I can't recall if I saw a torque spec or not for the tapered bearings when I did mine years ago, but I went by feel. It would be safe to assume that not everybody does this adjustment exactly the same way, so there could be tapered bearings out there that are adjusted too loosely so some shake remains.
There may also be a few people out there who tried re-torquing their OEM ball bearings and found a shake-resistant setting there as well. Martin is using OEM and I trust his ability to adjust and maintain them, so I'm going to consider his input to be best case for OEM. His claim above makes it sound like he still gets some shake at 3/4 tire life and beyond, but its not clear exactly how much from his post. He also seems to be unable to run radial tires at all without immediate problems. I switched mine over to tapered many years ago and got no shake at all at any point in the tire life from that point forward regardless of tire type, make, or model. I'd replace tires that were cupped, worn down to the cords, and still never had shake problems.
So in my case the tapered bearings made all the difference, and many others report the same result. If there are folks who have performed OEM bearing adjustments and achieved the same result, good for them, I'd like to hear their replies.